Periodontal disease (PD), which affects more than 60 million people, is the second most prevalent disease in the United States, yet less than one-fifth of Americans with periodontal disease receive treatment. Periodontal services require 150 million hours and $7 billion dollars annually. PD affects 80% of all adults and 90% of those between the ages of 55 and 64. It is estimated that 70 million adults suffer from some form of PD. Periodontal infections are now linked to cardiovascular disease, stroke, and diabetes making PD a serious health threat.
PD begins with a build up of plaque (which has bacteria in it) on a tooth. The bacteria in plaque attack the bone around the tooth, as well as the fibers (the periodontal ligament) that connect the tooth to the bone. As the fibers and bone are destroyed, a gingival pocket or space forms between the gum and the tooth—an ideal site for more plaque to build up. Left untreated, PD results in the destruction and recession of the periodontal ligament, which attaches the root of the tooth to the bone surface that makes up the interior of the tooth socket. The tooth attachments are destroyed in unpredictable site-specific pattern. Because public awareness of the disease is low and the early stages are painless, people generally don't floss that much, and as a result the disease progresses.
Unfortunately, because of the low awareness of the disease, it is generally not recognized until it has progressed to a significant degree. The treatment at this point, although effective, is uncomfortable, expensive, and often uncovered by insurance.
The accepted standard for measuring the progression of PD is to probe the gingival pocket to measure its depth and thereby measure the degree of recession of the periodontal ligament. The current gold standard for this measurement is a small ruler called a periodontal probe that is “poked” into the gum line to find and measure periodontal pockets and gum line detachments. The process is slow and painful, taking 10-15 minutes for some 180 measurements. Further, unless an automated recording system is used, the process requires the participation of two persons, one to take the measurements and a second to record the measurements. Recording of measurements is necessary to compare readings from one date to another to see if a pocket is breaking down. Because this is a tedious and painful process that is seldom done accurately or to completion, it is difficult to accurately identify and track the progress of the disease. The result is that the disease progresses insidiously and continually.
In addition to manual probing, another approach is disclosed in U.S. Pat. No. 5,755,571 to Companion. The probe disclosed in this patent uses intra-sulcular ultra-sound waves projected along the surface of the tooth for determining periodontal pocket depth. This method is less invasive with the mechanism, but injects a stream of water into the pocket to act as a transmission medium for ultra-sound waves. In addition to being a generally messy process, the injection of water into the root area of a tooth infected with PD can be the source of additional irritation of the area and discomfort to the patient. In addition, the water stream theoretically could mobilize the bacterium and cause cross contamination of sites. Further, the probe disclosed in Companion requires a fixed reference point, and uses the cemento-enamel junction (CEJ) as that reference point. The CEJ is the junction point between the enamel crown of a tooth and the cementum that makes up the root of the tooth. Establishing this reference point requires the use of an invasive probe that is incorporated with the ultra-sonic probe. Further, as disclosed in Companion, the CEJ is often difficult to locate or not present at all due to human variation and/or destruction of the CEJ.
A device known as the Florida probe uses a spring-loaded mechanism to detect the CEJ. Manual probing and the Florida probe are similar in that they invade the pocket to the base and make measurements from contact with the tissue at the bottom of the pocket. While considered to be superior to standard manual probing techniques, the Florida probe suffers from the same drawback as standard probing in that it is extremely invasive. In fact, the spring loaded mechanism of the Florida probe results in greater pressure being applied, and hence greater irritation to the gingival pocket. Further, the Florida probe suffers the same limitation as manual probing in that the presence of tartar in the pocket area may result in the determination of a false bottom for the pocket.
All of these methods approach the measurement of gingival pocket depth by varying levels of invasive measurement and are therefore likely to be uncomfortable for the patient and could prove cause for cross contamination.
U.S. Pat. No. 6,413,220 to Rose discloses a method and apparatus for using ultra-sonic waves for measuring the depth of a detachment between a tooth and its supporting tissue. Like the probe disclosed in Companion, the apparatus disclosed by Rose projects an intra-sulcular ultra-sound wave along the surface of a tooth (surface acoustic wave pulse) to determine pocket depth. The method and apparatus of Rose depend on achieving a particular critical angle of incidence between the tooth surface and the ultra-sonic probe. Therefore, repeatability of this method is highly dependent upon the skill of the operator.
Therefore, a need exists for a non-invasive method and apparatus for the identification and tracking of periodontal disease. Such a method would measure periodontal pocket depth non-invasively, and thereby enhance patient comfort. Therefore the method would reduce patient fears regarding examination of the gums and thereby make the public more likely to seek out the appropriate care and obtain early diagnosis and treatment. Such a method would further be easy to use, equivalent in complexity and time of use to current manual probes. Such a method would thereby offer repeatability, and the ability to track patient gum health, and given the new evidence of the relation of PD to systemic disease, make a serious improvement to public health.